I had the same problem and the following css sorted it out:
#tidio-plugin-container-right-bottom .tidio-element-corner > .tidio-text,
#tidio-plugin-container-left-bottom .tidio-element-corner > .tidio-text,
#tidio-plugin-container-right-middle .tidio-element-corner > .tidio-text,
#tidio-plugin-container-left-middle .tidio-element-corner > .tidio-text {
-webkit-filter: blur(0px)!important;
}